David F. Gray

This textbook describes the equipment, observational techniques, and analysis used in the investigation of stellar photospheres. Now in its fourth edition, the text has been thoroughly updated and revised to be more accessible to students. Meer

but when we state that A 'equals' B , as well having to know what we mean by A and B we also have know what we mean by 'equals'. This section explores the role of observers; how different types of observ­ er see different things as being equal, and how we can produce algo­ rithms to decide on such equalities. Meer